Empirical Modeling of Rough Surfaces and Subsurface Scatter

Over the last few decades we have developed a linear systems formulation of surface scatter theory that has led to a good understanding of surface scatter phenomena for clean, smooth (or moderately rough) optical surfaces, and to accurately predict the scattered light behavior [bidirectional scatter distribution function (BSDF)] from measured or assumed surface metrology data. However, for many applications there is a strong need to be able to accurately model scattered light behavior for surfaces or materials for which we have insufficient information or knowledge to develop or apply an accurate scatter theory. Due to the Helmholtz reciprocity theorem, useful empirical scattering models can be developed with limited experimental scattering data, even without knowledge or understanding of the actual scattering mechanism.